This invention relates to the creation of a sculpture generated by a laser beam directed at a transparent matrix, and more particularly, to a sculpture engraved within the surfaces of a transparent matrix.
There are many souvenirs and art objects wherein a translucent ghost-like image in two or three dimensions is seen floating within a solid piece of clear plastic or glass.
In recent years these translucent objects have been produced internally using a programmed laser that is brought to focus sequentially at many locations within the transparent matrix. The energy concentrated at the point of focus changes the matrix material so that the translucent three-dimensional object is created of many spots within the transparent plastic or glass matrix.
XYZ axis programming in positioning the matrix relative to the laser source provides enough spots (dots) within the matrix to define a desired image. Size of the spots can be controlled by controlling the energy and duration of the laser beam, and the size of the internal sculpture can be varied by setting the controls on the computer program.
The concentrated laser beam forms tiny cracks, that is, a destruction, in the matrix material at the point of beam focus and this cracking or other destruction provides the translucent regions which taken together create the sculpted shape. The amount of cracking or other distortion within the matrix is determined by the intensity and duration and type of the laser beam. In U.S. Pat. No. 5,575,936, the action of the laser beam is described as xe2x80x9clocal destructionxe2x80x9d or xe2x80x9clocal disruptionxe2x80x9d. In U.S. Pat. No. 5,886,318, the inventor describes a laser spot with a power density exceeding ten times the destruction threshold of the glass object under processing. At column 1, U.S. Pat. No. 5,637,244 speaks of xe2x80x9cmacro-destructionsxe2x80x9d. In the ""244 invention, the techniques were improved to provide xe2x80x9cmicrodestructionsxe2x80x9d adjustable in size. Clearly in the prior art, there is a degree of cracking/destruction at the point of concentration of the laser beam.
However, a problem arises when the laser spots/dots/cracks/destructions, etc. are too close together or too near the external surfaces of the matrix. Then, a defect in the internal sculpture results or subsequent changes with time may render the sculpture valueless. This internal damaging of the material limits the closeness of the dots that are generally formed in the prior art as well as their location relative to the outer surfaces of the matrix. The quality of the internal sculpture is adversely affected.
What is needed is a method of producing subsurface three dimensional sculpture by laser engraving that does not crack or destroy the matrix material in order to form the sculpture, thereby permitting a finer sculpture with closer xe2x80x9cdotsxe2x80x9d and an ability to locate the internal sculpture at or near external surfaces of the matrix without later changes or interactions.
In accordance with the invention an improved sculpturing procedure results in an improved product. In such subsurface sculpting, clear materials, whether glass or plastic, are generally used as the matrix materials. These matrix materials may be in three states, namely, liquid, gelatinous, and solid. In the prior art, the laser sculpting has been done in solid material. The matrix is formed into the desired shape by pouring liquid material into a mold that has been prepared, for example, in special instances, by an artist. With time, the material progresses from the liquid state to the gelatinous state and finally to the solid state. Thereafter, laser sculpting commences in the known manner.
In accordance with the present invention, the laser sculpting steps are performed when the matrix material is still in a gelatinous condition. As a result, small spots, dots or bubbles are formed, which are tiny, and because the material is a non-solid gel when the laser beam applies its focused energy, there is no cracking or destruction. What the actual process in formation of the spots/dots/bubbles is, is not precisely known. It is not known whether the matrix material locally evaporates, for example, or perhaps the dots/bubbles are the result of some chemical process that occurs by the application of high intensity thermal energy. However, it has been found possible to link dot to dot and even draw continuous lines with the laser beam. This is not possible in the prior art where the material is cracked/destroyed, as the thermal energy is applied to a solid. Intensity and duration of the laser pulse in the present invention determine the size of the dots/bubbles that are produced as does the timing in relation to the matrix material finally changing from gel to solid. All of the possible conditions between the liquid state and the solid state for the matrix material have not yet been explored in actual sculpting. Particular visual effects can be expected at different degrees of solidity when sculpting.
Thus, there is a wide range of control of the internal sculpture that is produced. Additionally, sculpting can be performed on the external surfaces of the matrix as well as close to these external surfaces without cracking/destruction. Spacing between dots and lines allow for the production of a three-dimensional-translucent, see-through sculpture, floating ghost-like in a clear matrix. The matrix material may be colorless or tinted so long as it remains sufficiently clear to permit the laser beam penetration from its external position.
The liquid in the mold may be pressurized for removal of air bubbles after initial pouring of the matrix material into the mold, and application of pressure on an exposed surface of the matrix after the laser sculpting can be used to control the size of the dots/bubbles that result in the finished product.
Because the sculpting is performed on a matrix in a semi-solid, that is, somewhat gelatinous state, there is no cracking of the matrix material, and a finer detailing of the finished sculpture is possible.
Accordingly, it is an object of the invention to provide an improved method for subsurface engraving of a three-dimensional sculpture within a transparent matrix.
Another object of the invention is to provide an improved method for subsurface engraving three-dimensional sculpture within a transparent matrix wherein dots/bubbles may be joined one to the other, or in a continuous line.
Yet another object of the invention is to provide an improved subsurface engraving of a three-dimensional sculpture in a transparent matrix wherein the sculpture is both on the surface of the matrix and within the matrix.
Still another object of the invention is to provide an improved subsurface engraving of a three-dimensional sculpture within a transparent matrix, wherein the sculpture is close to an external surface of the matrix.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the article possessing the features, properties and the relation of elements, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.
Still other objects and advantages of the invention will be apparent from the specification.